scholarly journals Molecular cloning and expression of human cDNAs encoding a novel DNA ligase IV and DNA ligase III, an enzyme active in DNA repair and recombination.

1995 ◽  
Vol 15 (6) ◽  
pp. 3206-3216 ◽  
Author(s):  
Y F Wei ◽  
P Robins ◽  
K Carter ◽  
K Caldecott ◽  
D J Pappin ◽  
...  

Three distinct DNA ligases, I to III, have been found previously in mammalian cells, but a cloned cDNA has been identified only for DNA ligase I, an essential enzyme active in DNA replication. A short peptide sequence conserved close to the C terminus of all known eukaryotic DNA ligases was used to search for additional homologous sequences in human cDNA libraries. Two different incomplete cDNA clones that showed partial homology to the conserved peptide were identified. Full-length cDNAs were obtained and expressed by in vitro transcription and translation. The 103-kDa product of one cDNA clone formed a characteristic complex with the XRCC1 DNA repair protein and was identical with the previously described DNA ligase III. DNA ligase III appears closely related to the smaller DNA ligase II. The 96-kDa in vitro translation product of the second cDNA clone was also shown to be an ATP-dependent DNA ligase. A fourth DNA ligase (DNA ligase IV) has been purified from human cells and shown to be identical to the 96-kDa DNA ligase by unique agreement between mass spectrometry data on tryptic peptides from the purified enzyme and the predicted open reading frame of the cloned cDNA. The amino acid sequences of DNA ligases III and IV share a related active-site motif and several short regions of homology with DNA ligase I, other DNA ligases, and RNA capping enzymes. DNA ligases III and IV are encoded by distinct genes located on human chromosomes 17q11.2-12 and 13q33-34, respectively.

1995 ◽  
Vol 15 (10) ◽  
pp. 5412-5422 ◽  
Author(s):  
J Chen ◽  
A E Tomkinson ◽  
W Ramos ◽  
Z B Mackey ◽  
S Danehower ◽  
...  

Three biochemically distinct DNA ligase activities have been identified in mammalian cell extracts. We have recently purified DNA ligase II and DNA ligase III to near homogeneity from bovine liver and testis tissue, respectively. Amino acid sequencing studies indicated that these enzymes are encoded by the same gene. In the present study, human and murine cDNA clones encoding DNA ligase III were isolated with probes based on the peptide sequences. The human DNA ligase III cDNA encodes a polypeptide of 862 amino acids, whose sequence is more closely related to those of the DNA ligases encoded by poxviruses than to replicative DNA ligases, such as human DNA ligase I. In vitro transcription and translation of the cDNA produced a catalytically active DNA ligase similar in size and substrate specificity to the purified bovine enzyme. The DNA ligase III gene was localized to human chromosome 17, which eliminated this gene as a candidate for the cancer-prone disease Bloom syndrome that is associated with DNA joining abnormalities. DNA ligase III is ubiquitously expressed at low levels, except in the testes, in which the steady-state levels of DNA ligase III mRNA are at least 10-fold higher than those detected in other tissues and cells. Since DNA ligase I mRNA is also present at high levels in the testes, we examined the expression of the DNA ligase genes during spermatogenesis. DNA ligase I mRNA expression correlated with the contribution of proliferating spermatogonia cells to the testes, in agreement with the previously defined role of this enzyme in DNA replication. In contrast, elevated levels of DNA ligase III mRNA were observed in primary spermatocytes undergoing recombination prior to the first meiotic division. Therefore, we suggest that DNA ligase III seals DNA strand breaks that arise during the process of meiotic recombination in germ cells and as a consequence of DNA damage in somatic cells.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Benoit Roch ◽  
Vincent Abramowski ◽  
Olivier Etienne ◽  
Stefania Musilli ◽  
Pierre David ◽  
...  

We developed a Xrcc4M61R separation of function mouse line to overcome the embryonic lethality of Xrcc4 deficient mice. XRCC4M61R protein does not interact with Xlf, thus obliterating XRCC4-Xlf filament formation while preserving the ability to stabilize DNA Ligase IV. X4M61R mice, which are DNA repair deficient, phenocopy the Nhej1-/- (known as Xlf -/-) setting with a minor impact on the development of the adaptive immune system. The core NHEJ DNA repair factor XRCC4 is therefore not mandatory for V(D)J recombination aside from its role in stabilizing DNA ligase IV. In contrast, Xrcc4M61R mice crossed on Paxx-/-, Nhej1-/-, or Atm-/- backgrounds are severely immunocompromised, owing to aborted V(D)J recombination as in Xlf-Paxx and Xlf-Atm double KO settings. Furthermore, massive apoptosis of post-mitotic neurons causes embryonic lethality of Xrcc4M61R -Nhej1-/- double mutants. These in vivo results reveal new functional interplays between XRCC4 and PAXX, ATM and Xlf in mouse development and provide new insights in the understanding of the clinical manifestations of human XRCC4 deficient condition, in particular its absence of immune deficiency.


2020 ◽  
Vol 48 (7) ◽  
pp. 3708-3721 ◽  
Author(s):  
Melike Çağlayan

Abstract DNA ligase I and DNA ligase III/XRCC1 complex catalyze the ultimate ligation step following DNA polymerase (pol) β nucleotide insertion during base excision repair (BER). Pol β Asn279 and Arg283 are the critical active site residues for the differentiation of an incoming nucleotide and a template base and the N-terminal domain of DNA ligase I mediates its interaction with pol β. Here, we show inefficient ligation of pol β insertion products with mismatched or damaged nucleotides, with the exception of a Watson–Crick-like dGTP insertion opposite T, using BER DNA ligases in vitro. Moreover, pol β N279A and R283A mutants deter the ligation of the promutagenic repair intermediates and the presence of N-terminal domain of DNA ligase I in a coupled reaction governs the channeling of the pol β insertion products. Our results demonstrate that the BER DNA ligases are compromised by subtle changes in all 12 possible noncanonical base pairs at the 3′-end of the nicked repair intermediate. These findings contribute to understanding of how the identity of the mismatch affects the substrate channeling of the repair pathway and the mechanism underlying the coordination between pol β and DNA ligase at the final ligation step to maintain the BER efficiency.


2017 ◽  
Vol 28 ◽  
pp. v17
Author(s):  
D. Aceytuno ◽  
C.G. Piett ◽  
Z. Havali-Shahriari ◽  
R.A. Edwards ◽  
M. Rey ◽  
...  

2008 ◽  
Vol 29 (5) ◽  
pp. 1116-1122 ◽  
Author(s):  
Laurent Malivert ◽  
Isabelle Callebaut ◽  
Paola Rivera-Munoz ◽  
Alain Fischer ◽  
Jean-Paul Mornon ◽  
...  

ABSTRACT The core nonhomologous end-joining DNA repair pathway is composed of seven factors: Ku70, Ku80, DNA-PKcs, Artemis, XRCC4 (X4), DNA ligase IV (L4), and Cernunnos/XLF (Cernunnos). Although Cernunnos and X4 are structurally related and participate in the same complex together with L4, they have distinct functions during DNA repair. L4 relies on X4 but not on Cernunnos for its stability, and L4 is required for optimal interaction of Cernunnos with X4. We demonstrate here, using in vitro-generated Cernunnos mutants and a series of functional assays in vivo, that the C-terminal region of Cernunnos is dispensable for its activity during DNA repair.


2003 ◽  
Vol 14 (2) ◽  
pp. 685-697 ◽  
Author(s):  
Marcin R. Przewloka ◽  
Paige E. Pardington ◽  
Steven M. Yannone ◽  
David J. Chen ◽  
Robert B. Cary

Several findings have revealed a likely role for DNA ligase IV, and interacting protein XRCC4, in the final steps of mammalian DNA double-strand break repair. Recent evidence suggests that the human DNA ligase IV protein plays a critical role in the maintenance of genomic stability. To identify protein–protein interactions that may shed further light on the molecular mechanisms of DSB repair and the biological roles of human DNA ligase IV, we have used the yeast two-hybrid system in conjunction with traditional biochemical methods. These efforts have resulted in the identification of a physical association between the DNA ligase IV polypeptide and the human condensin subunit known as hCAP-E. The hCAP-E polypeptide, a member of the Structural Maintenance of Chromosomes (SMC) super-family of proteins, coimmunoprecipitates from cell extracts with DNA ligase IV. Immunofluorescence studies reveal colocalization of DNA ligase IV and hCAP-E in the interphase nucleus, whereas mitotic cells display colocalization of both polypeptides on mitotic chromosomes. Strikingly, the XRCC4 protein is excluded from the area of mitotic chromosomes, suggesting the formation of specialized DNA ligase IV complexes subject to cell cycle regulation. We discuss our findings in light of known and hypothesized roles for ligase IV and the condensin complex.


RSC Advances ◽  
2016 ◽  
Vol 6 (97) ◽  
pp. 94574-94587 ◽  
Author(s):  
Deependra Kumar Singh ◽  
Mohd. Kamil Hussain ◽  
Shagun Krishna ◽  
Amit Laxmikant Deshmukh ◽  
Mohammad Shameem ◽  
...  

The compound S-097/98 is a specific inhibitor of hLig1. As shown in the figure, the compound inhibits only hLig1 while other human and non-human DNA ligases are not inhibited.


2015 ◽  
Vol 112 (20) ◽  
pp. E2575-E2584 ◽  
Author(s):  
Dylan A. Reid ◽  
Sarah Keegan ◽  
Alejandra Leo-Macias ◽  
Go Watanabe ◽  
Natasha T. Strande ◽  
...  

Nonhomologous end-joining (NHEJ) is a major repair pathway for DNA double-strand breaks (DSBs), involving synapsis and ligation of the broken strands. We describe the use of in vivo and in vitro single-molecule methods to define the organization and interaction of NHEJ repair proteins at DSB ends. Super-resolution fluorescence microscopy allowed the precise visualization of XRCC4, XLF, and DNA ligase IV filaments adjacent to DSBs, which bridge the broken chromosome and direct rejoining. We show, by single-molecule FRET analysis of the Ku/XRCC4/XLF/DNA ligase IV NHEJ ligation complex, that end-to-end synapsis involves a dynamic positioning of the two ends relative to one another. Our observations form the basis of a new model for NHEJ that describes the mechanism whereby filament-forming proteins bridge DNA DSBs in vivo. In this scheme, the filaments at either end of the DSB interact dynamically to achieve optimal configuration and end-to-end positioning and ligation.


DNA Repair ◽  
2014 ◽  
Vol 21 ◽  
pp. 97-110 ◽  
Author(s):  
Sehyun Oh ◽  
Adam Harvey ◽  
Jacob Zimbric ◽  
Yongbao Wang ◽  
Thanh Nguyen ◽  
...  

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